From Kishanganj, the Ganges and its tributaries are divided into the plains of the entire West Bengal, from which a Delta region is formed. These forests are found in the seaward swampy area are called the Sunderbans. It is a protected area in both India and Bangladesh. This is one of the leading areas of the world in terms of bio – diversity. Here, mangrove and tidal type of vegetation is found. The forests have been named after the large number of ‘Sundari tree’ species found here.